WINSTON-SALEM, N.C., Feb 5 (Reuters) - Former "American Idol" singer Clay Aiken said on Wednesday he will run for U.S. Congress as a Democrat in his home state of North Carolina, where he once worked as a special education teacher.

Aiken, 35, is likely to face a tough battle in his efforts to unseat Representative Renee Ellmers, a Tea Party Republican favorite, in the state's conservative 2nd congressional district.

The entertainer tried to position himself as a political outsider who wants to change Washington by giving a voice to people in need.

"I'm not a politician," he said in a video on his campaign website. "I don't ever want to be one."

Aiken described past challenges he had faced after his mother left his abusive father and worked hard to provide what little she could for his family.

He filmed the video in a small North Carolina home where he said he and his mother slept for months on a mattress in a friend's living room when he was young.

He noted his work teaching children with autism and his international travels with aid organization UNICEF, bookends to his runner-up finish in 2003 on the "American Idol" television talent show that thrust him into the national spotlight.

"If you only know the part of my story that begins with a golden ticket, something that still seems unbelievable to me even to this day, you might wonder what would qualify me to run," Aiken said. "Well it starts with a life I remember all too well."

Aiken is one of the more successful "American Idol" contestants, having since released solo albums and appearing on Broadway in the spoof musical "Monty Python's Spamalot." He also appeared on "The Celebrity Apprentice" TV show with Donald Trump.

In 2008, Aiken acknowledged he is gay and said he decided to come out after becoming a father that year.

His decision to seek the Democratic nomination followed weeks of speculation that he would enter the race.

He said Ellmers, who was first elected to the House of Representatives in 2010, had hurt North Carolinians with votes that shut down the federal government and cut military spending.

A spokeswoman for Ellmers did not immediately respond to a request for comment.

Asked last week whether she considered Aiken a serious candidate, the congresswoman joked about his second-place finish in the talent competition.

"He didn't really fare all that well," Ellmers said in an interview on WMAL Radio in Washington. "He was runner-up."

"Apparently his performing career is not going so well and he's very bored," she said, adding that she thinks Aiken is a talented singer. (Reporting by Colleen Jenkins; editing by Scott Malone, James Dalgleish and G Crosse)